1. Field of the Invention
The present invention relates to small sealed handheld laser systems, which fulfill all clinical use requirements and which can be operated simply. In particular, this invention refers to laser hand-pieces for use in the dental field.
2. Invention Disclosure Statement
The general problem with medical or dental devices that employ electrical and/or mechanical tools is that it is difficult to separate the circuits and/or the machinery from parts of the body that don't require treatment. Any proximity between the patient and the working components that make up the treatment device, increases the risk of harm to the patient. The shielding materials used in the prior art however, increase the device size and restrict the treatment area. This restriction in treatment area size often means that a treatment can not be performed as effectively. This lack of efficiency can also mean that the medical procedure is not cost effective.
A typical hand-piece in the prior art consists of a drill and an electric power source in proximity to the patient. For example, U.S. Pat. No. 5,785,521 describes a combination drill and fluid conditioning system that delivers various fluids to the dental area. This system has the advantage of delivering fluids during drilling, but the device still has an electrically powered drill incorporated into the hand-piece.
Since electrical wiring imposes a multitude of safety restrictions, medical instruments need some alternative energy source. The prior art has made several attempts to solve this problem. In laser instruments, one solution has been to employ optical fibers to guide radiation from a peripheral laser source to the hand-piece and treatment site. This is illustrated in U.S. Pat. No. 5,310,344, which describes a state of the art dental laser system where the optical fiber is a single crystal sapphire strand. This sapphire strand is used to connect the laser housing to a dental hand-piece some distance away. The drawback to this concept is that optical fibers, especially crystal strands, can often break.
Another solution in laser dental applications has been to directly image laser radiation to the treatment site as described in U.S. Pat. No. 5,846,080. This system images laser radiation from a laser source in the system, to the distal end treatment site. This type of laser system however, is very cumbersome and is difficult to utilize in dentistry applications.
It is important to find a practical way to deliver laser radiation to the mouth region because lasers have multiple applications in dentistry. U.S. Pat. No. 5,192,279 describes the use of laser radiation to safely remove a carious lesion, desensitize the treatment area, or seal a dental tissue surface. U.S. Pat. No. 5,622,501 describes a system where the laser source is used in conjunction with a photochemical to destroy bacteria on tooth surfaces or in the oral cavity.
In the prior art, another solution to avoid the use of electricity in proximity to the patient has been to use liquid or gaseous streams in the place of an electric device. These fluid streams are delivered through a channel system to the hand-pieces. The use of pneumatic tools is applicable in dental drilling, to aspirate an area or to supply photodynamic substances, abrasive fluids, or anaesthetic drugs. This type of system can be used in abrasion or disinfecting procedures. U.S. Pat. No. 5,759,031 and U.S. Pat. No. 5,752,829 describe an abrasive air system for use in the dental field. Its primary feature is an air abrasive drill system that is more accurate than previous air abrasive systems. This system incorporates a vacuum system to remove the abrasive materials as well as means for illuminating the target site. The problem with this invention is that it is a separate piece of equipment that is not necessarily compatible with any existing equipment.
One final solution, to avoid having electrical components in proximity with the patient, is the concept of a turbine dental drill. U.S. Pat. No. 3,932,055 describes a vacuum turbine dental drill. This invention has only limited applications since any other device that requires electrical energy cannot be used. Likewise, this invention can only be combined with a radiation source if optical fibers are used to reach the treatment area.
Various dental applications are generally accomplished by using a specialized hand-piece. The hand-pieces are manufactured to suit a particular application or treatment type. The hand-pieces must also be connected to a specific peripheral supply system. U.S. Pat. No. 5,851,112 describes an optical fiber hand-piece for use in various oral treatments. This hand-piece only incorporates a laser and any other devices needed for a procedure must be separately contained. U.S. Pat. No. 5,897,314 describes a hand-piece that is designed specifically for a root canal treatment. This hand-piece has limited used because it is a separate tool that can only be used for a single type of procedure.
The prior art has several problems that limit the use of lasers in dental applications. First each hand-piece system must be manufactured for a specific application. If a fiber is used to connect the hand-piece to a peripheral laser system, the fiber can only be used over limited distances. Although fibers are flexible, there is the danger of potential fiber breakage that would cause the device to malfunction. The fibers therefore must be protected with a surrounding material or sleeve to reduce the risk of breakage. Another difficulty is that the laser source must be part of a separate peripheral device with it's own cooling and power supply. Any other instruments needed for a procedure must be contained in a separate apparatus that has its own power supply. This limitation increases the space and cost requirements for implementing laser procedures. It is the goal of the present invention to provide a solution to these problems in the prior art.